Lecture 2: Fossil Record...Autonomic Nervous System (ANS) • Outside of our conscious awareness • Regulates body temperature • Coordinates cardiovascular, respiratory, digestive,
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Lecture 2: Fossil Record
BIOL 4260 Human Evolutionary Anatomy
Lecture 18: Cranial Nerves
Somatic vs. Autonomic Nervous Systems • Autonomic nervous system
– Axons innervate the visceral organs – Afferent pathways originate in the
visceral receptors • Somatic nervous system
– Axons innervate the skeletal muscles
– Afferent pathways originate in the skeletal muscles
Autonomic Nervous System (ANS)
• Outside of our conscious awareness
• Regulates body temperature
• Coordinates cardiovascular, respiratory, digestive, excretory, and reproductive functions
Thoracic nerves
T1 T2 T3 T4 T5 T6 T7 T8
AUTONOMIC NERVOUS SYSTEM
THORACOLUMBAR DIVISION (sympathetic
division of ANS)
CRANIOSACRAL DIVISION (parasympathetic division of ANS)
Cranial nerves (N III, N VII, N IX,
and N X)
AUTONOMIC NERVOUS SYSTEM
Consists of 2 divisions
SYMPATHETIC (thoracolumbar)
DIVISION
PARASYMPATHETIC (craniosacral)
DIVISION
Preganglionic neurons in
lateral gray horns of spinal segments T1–L2
Preganglionic neurons in brain
stem and in lateral portion of anterior gray horns of S2–S4
Send preganglionic fibers to
Which send postganglionic fibers to
Ganglia near spinal cord
Ganglia in or near target organs
Preganglionic fibers release ACh (excitatory),
stimulating ganglionic neurons
Preganglionic fibers release ACh (excitatory),
stimulating ganglionic neurons
Target organs Target organs
Most postganglionic fibers release NE at
neuroeffector junctions
All postganglionic fibers release ACh at
neuroeffector junctions
“Fight or flight” response
“Rest and repose” response
Functional components of the ANS
The Parasympathetic Division
• Functions: – Pupil constriction – Secretion of digestive enzymes from digestive
glands – Increased smooth muscle activity of the
digestive system – Stimulation and coordination of defecation – Contraction of the urinary bladder – Constriction of respiratory passages – Reduced heart rate – Sexual arousal
Pterygopalatine ganglion
PONS
N III
N VII
N IX
N X (Vagus)
Ciliary ganglion
Submandibular ganglion
Otic ganglion
Autonomic plexuses (see Figure 17.9)
Pelvic nerves
Lacrimal gland
Eye
Salivary glands
Heart
Lungs
Liver and gallbladder
Stomach
Spleen
Pancreas
Large intestine
Small intestine
Rectum
Kidney
Urinary bladder Scrotum Penis Ovary Uterus
S2
S3
S4
Spinal cord
Preganglionic neurons Ganglionic neurons
KEY
The Cranial Nerves
• There are 12 pairs of cranial nerves – These nerves innervate the periphery emerging
from the brain (not the spinal cord) – These nerves are on the ventrolateral surface of
the brain – They are numbered beginning at the anterior
aspect of the brain – They are numbered CN I to CN XII
The Cranial Nerves
Figure 16.22b Origins of the Cranial Nerves
Diagrammatic inferior view of the human brain. Compare view with part (a).
Olfactory bulb, termination of olfactory nerve (N I)
Olfactory tract
Optic chiasm
Optic nerve (N II)
Infundibulum
Oculomotor nerve (N III)
Trochlear nerve (N IV)
Trigeminal nerve (N V)
Abducens nerve (N VI)
Facial nerve (N VII)
Vestibulocochlear nerve (N VIII)
Glossopharyngeal nerve (N IX)
Vagus nerve (N X)
Hypoglossal nerve (N XII)
Accessory nerve (N XI)
The inferior surface of the brain as it appears on gross dissection. The roots of the cranial nerves are clearly visible.
Medulla oblongata
Spinal cord
Cerebellum
Vertebral artery
Basilar artery
Mamillary body
Pons
Olfactory bulb, termination of olfactory nerve (N I)
Olfactory tract
Optic chiasm
Optic nerve (N II)
Infundibulum
Oculomotor nerve (N III)
Trochlear nerve (N IV)
Trigeminal nerve (N V)
Abducens nerve (N VI)
Facial nerve (N VII)
Vestibulocochlear nerve (N VIII)
Glossopharyngeal nerve (N IX)
Vagus nerve (N X)
Hypoglossal nerve (N XII)
Accessory nerve (N XI)
The Cranial Nerves
• CN I: The Olfactory Nerve – Function: sensory (smell) – Origin: olfactory epithelium – Foramen: olfactory foramina – Destination: olfactory bulbs
Olfactory nerve fibers
Olfactory epithelium
Cribriform plate of ethmoid
OLFACTORY NERVE (N I)
Olfactory tract (to olfactory cortex
of cerebrum)
Left olfactory bulb (termination of olfactory nerve)
Figure 18.6a The Olfactory Organs
The distribution of the olfactory receptors on the left side of the nasal septum is shown by the shading.
Olfactory bulb
Olfactory nerve fibers (N I)
Olfactory tract
Cribriform plate of ethmoid
Olfactory epithelium
The Cranial Nerves
• CN II: The Optic Nerve – Function: sensory (vision) – Origin: retina – Foramen: optic canal – Destination: diencephalon, then to occipital
lobe
OPTIC NERVE (N II)
Mesencephalon (cut)
Optic chiasm
Optic tract
Eye
Visual cortex (in occipital lobes)
Optic projection fibers
Lateral geniculate nucleus (in thalamus)
Pituitary gland
Olfactory tract Olfactory bulb
The Cranial Nerves
• CN III: The Oculomotor Nerve – Function: controls extra-ocular eye muscles
• Motor function • Superior, inferior, and medial rectus • Inferior oblique • Levator palpebrae superioris
– Origin: mesencephalon – Foramen: superior orbital fissure – Destination: extra-ocular eye muscles
Trigeminal nerve (N V), cut
Vestibulocochlear nerve (N VIII), cut
Facial nerve (N VII), cut
ABDUCENS NERVE (N VI)
Lateral rectus muscle (cut)
Medial rectus muscle
Inferior rectus muscle
Ciliary ganglion
OPTIC NERVE (N II)
Optic chiasm
OCULOMOTOR NERVE (N III)
TROCHLEAR NERVE (N IV)
Superior rectus muscle Superior
oblique muscle
Trochlea
Levator palpebrae superioris
muscle
Inferior oblique muscle
The Cranial Nerves
• CN IV: The Trochlear Nerve – Function: controls extra-ocular eye muscles
• Motor function • Superior oblique
– Origin: mesencephalon – Foramen: superior orbital fissure – Destination: extra-ocular eye muscles
Trigeminal nerve (N V), cut
Vestibulocochlear nerve (N VIII), cut
Facial nerve (N VII), cut
ABDUCENS NERVE (N VI)
Lateral rectus muscle (cut)
Medial rectus muscle
Inferior rectus muscle
Ciliary ganglion
OPTIC NERVE (N II)
Optic chiasm
OCULOMOTOR NERVE (N III)
TROCHLEAR NERVE (N IV)
Superior rectus muscle Superior
oblique muscle
Trochlea
Levator palpebrae superioris
muscle
Inferior oblique muscle
The Cranial Nerves
• CN V: The Trigeminal Nerve – Function:
• Mixed (sensory and motor) function • Ophthalmic: sensations from the forehead, eyelids, and
nose • Maxillary: sensations from lower eyelid, upper lip, and
cheek • Mandibular: controls mastication
– Origin: ophthalmic, maxillary, and mandibular nerves
The Cranial Nerves
• CN V: The Trigeminal Nerve (continued) – Foramen:
• Ophthalmic: superior orbital fissure • Maxillary: foramen rotundum • Mandibular: foramen ovale
– Destination: • Ophthalmic and maxillary: Pons • Mandibular: mandibular muscles
TRIGEMINAL NERVE (N V)
Maxillary branch
Foramen ovale
Pons
Otic ganglion
Mandibular branch
Pterygopalatine ganglion
Ophthalmic branch
Semilunar ganglion
Superior orbital fissure
Supraorbital nerves
Ciliary ganglion
Foramen rotundum
Infra-orbital nerve
Lingual nerve
Submandibular ganglion
Mental nerve
The Cranial Nerves
• CN VI: The Abducens Nerve – Function: controls eye movements
• Motor function
– Origin: pons – Foramen: superior orbital fissure – Destination: innervates the lateral rectus eye
muscle
Trigeminal nerve (N V), cut
Vestibulocochlear nerve (N VIII), cut
Facial nerve (N VII), cut
ABDUCENS NERVE (N VI)
Lateral rectus muscle (cut)
Medial rectus muscle
Inferior rectus muscle
Ciliary ganglion
OPTIC NERVE (N II)
Optic chiasm
OCULOMOTOR NERVE (N III)
TROCHLEAR NERVE (N IV)
Superior rectus muscle Superior
oblique muscle
Trochlea
Levator palpebrae superioris
muscle
Inferior oblique muscle
The Cranial Nerves
• CN VII: The Facial Nerve – Function: Mixed (sensory and motor)
• Sensory: sensations from the face / taste • Motor: controls muscles of the face
– Origin: • Sensory: taste buds • Motor: pons
– Foramen: internal acoustic meatus – Destination:
• Sensory: pons • Motor: muscles of the face
Origin and branches of the facial nerve
Posterior auricular branch
Stylomastoid foramen
Chorda tympani nerve (with mandibular branch of N V)
Lingual branch (with lingual nerve of N V)
Submandibular ganglion
Pons
Pterygopalatine ganglion
Greater petrosal nerve
Geniculate ganglion
FACIAL NERVE (N VII)
Temporal branch
Zygomatic branches
Buccal branch
Mandibular branch
Cervical branch
The Cranial Nerves
• CN VIII: The Vestibulocochlear Nerve – Function:
• Sensory: balance and hearing
– Origin: receptors of the vestibule and cochlea – Foramen: internal acoustic meatus – Destination: pons
Tympanic cavity
(middle ear) Semicircular
canals
Vestibular branch
(N VIII)
Facial nerve
(N VII), cut
Internal acoustic canal
VESTIBULOCOCHLEAR NERVE (N VIII)
Pons
N V
N VI N VII
N IX N XII N X
N XI
Medulla oblongata
Cochlear branch (N VIII)
Cochlea Auditory tube
Tympanic membrane
The Cranial Nerves
• CN IX: The Glossopharyngeal Nerve – Function: Mixed (sensory and motor)
• Sensory function: tongue pain • Motor function: swallowing
– Origin: • Sensory: posterior 1/3 of the tongue • Motor: salivary gland
The Cranial Nerves
• CN IX: The Glossopharyngeal Nerve (continued)
– Foramen: jugular foramen – Destination:
• Sensory: pons • Visceral motor: parotid salivary gland • Somatic motor: pharyngeal muscles for swallowing
Common carotid artery
Carotid sinus
Carotid body
Lingual branch
Otic ganglion
Inferior (petrosal) ganglion
GLOSSOPHARYNGEAL NERVE (N IX)
Superior (jugular) ganglion
Pharyngeal branches
Carotid sinus branch
Parotid salivary gland
Medulla oblongata
Pons
N VII
N VI
N V
N VIII
The Cranial Nerves
• CN X: The Vagus Nerve – Function:
• Sensory: information from organs • Motor: sends information to the organs
– Origin: • Sensory: from the organs • Motor: medulla oblongata
The Cranial Nerves
• CN X: The Vagus Nerve (continued) – Foramen: jugular foramen – Destination:
• Sensory: autonomic centers of the medulla oblongata • Somatic motor: muscles of the palate and pharynx • Visceral motor: respiratory, cardiovascular, and
digestive organs
Superior pharyngeal
branch
Superior laryngeal nerve
Recurrent laryngeal nerve
Internal branch
External branch
VAGUS NERVE (N X)
Inferior ganglion of vagus nerve
Cardiac branches
Cardiac plexus
Anterior vagal trunk
Left lung Right lung
Liver
Stomach
Colon
Pancreas
Spleen
Small intestine
Celiac plexus
Hypogastric plexus
Medulla oblongata
Auricular branch to external ear
Superior ganglion of vagus nerve
Pharyngeal branch
Superior laryngeal nerve
The Cranial Nerves
• CN XI: The Accessory Nerve – Function:
• Motor: controls the sternocleidomastoid, trapezius, palate, pharynx, and larynx muscles
– Origin: spinal cord and medulla oblongata – Foramen: jugular foramen – Destination:
• Internal branch: muscles of the palate, pharynx, and larynx
• External branch: sternocleidomastoid and trapezius muscles
HYPOGLOSSAL NERVE (N XII)
ACCESSORY NERVE (N XI)
Internal branch: to palatal, pharyngeal, and laryngeal muscles with vagus nerve
Intrinsic muscles of tongue
Styloglossus muscle
Genioglossus muscle
Geniohyoid muscle Hyoglossus muscle
Hyoid bone
Thyrohyoid muscle
Sternohyoid muscle
Sternothyroid muscle
Omohyoid muscle
Sternocleidomastoid muscle
Trapezius muscle
Ansa cervicalis (cervical plexus)
Spinal cord
External branch of N XI
Spinal root of N XI
Cranial root of N XI
Trigeminal nerve (N V)
Medulla oblongata
The Cranial Nerves
• CN XII: The Hypoglossal Nerve – Function:
• Motor: controls tongue movement
– Origin: medulla oblongata – Foramen: hypoglossal canal – Destination: tongue muscles
HYPOGLOSSAL NERVE (N XII)
ACCESSORY NERVE (N XI)
Internal branch: to palatal, pharyngeal, and laryngeal muscles with vagus nerve
Intrinsic muscles of tongue
Styloglossus muscle
Genioglossus muscle
Geniohyoid muscle Hyoglossus muscle
Hyoid bone
Thyrohyoid muscle
Sternohyoid muscle
Sternothyroid muscle
Omohyoid muscle
Sternocleidomastoid muscle
Trapezius muscle
Ansa cervicalis (cervical plexus)
Spinal cord
External branch of N XI
Spinal root of N XI
Cranial root of N XI
Trigeminal nerve (N V)
Medulla oblongata
CRANIAL NERVES Oh, Once One Takes The Anatomy Final, Very Good Vacations Are Heavenly! Some Say Marry Money, But My Brother Says Big Business Makes Money! (sensory/motor/both)
#
Name
SMB
From
To
I
Olfactory
S
olfactory epithelium
cerebrum
II
Optic
S
retina
thalamus
III
Occulomotor
M
eye muscles
midbrain
IV
Trochlear
M
eye muscle SO
midbrain
V
Trigeminal
B
eye + jaw area
pons
VI
Abducens
M
eye muscle LR
pons
VII
Facial
B
motor + sensory of face area
pons
VIII
Vestibulocochlear (Acoustic)
S
inner ear
pons + medulla oblongata
IX
Glossopharyngeal
B
tongue + pharynx
medulla oblongata
X
Vagus
B
visceral organs
medulla oblongata
XI
Accessory (Spinal Acc.)
M
pharynx + neck muscles
medulla oblongata + spinal cord
XII
Hypoglossal
M
tongue muscles
medulla oblongata
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